For this study, we will enroll 46 patients with failed back surgery syndrome believed to be secondary to perineural fibrosis in a randomized, double-blinded, controlled clinical trial. We will assign patients to one of two groups before surgery: preoperative radiation (treatment group) or no preoperative radiation (control group). We will treat half of the patients with external beam radiation before re-exploration and decompression of their peridural fibrosis (treatment group) and perform re-exploration and decompression in the other half without preoperative radiation (control group).